"Toughness" of CPE [Archive] - Ceramic Tile Advice Forums - John Bridge Ceramic Tile


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12-11-2016, 09:47 PM
New hear but have been doing some extensive searching. Did my first CPE pan last week, BUT I installed 15lb roofing felt under it, just as an underlayment.

I've read Byrne's book about roofing cement, and I have seen some threads on hear about using roofing cement on CPE without problems. Ive also read some stuff about asphalt drying out the CPE?

I am going to call nobel in the morning, but just want to see what advice I can pick up here. Do I need to rip this liner out? Will the paper be a problem?

If I should take the paper out, can I just try and lift the pan away from the walls and try and pull the paper out?


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12-11-2016, 09:57 PM
Welcome, Mike. :)

Did you place a proper pre-slope before you installed your felt and CPE pan liner?

12-11-2016, 10:06 PM

Thanks for getting back so fast. (I've read tons of your posts)

Yes, I have a preslope, 1/4 per foot. I also have blocking between all the studs. After the preslope I have the 15 lb felt as an underlayment, CPE liner on top of that. Noble 150 at the drain and for the preform corners.

This is my first "plastic" liner. I come from the world of lead.


12-11-2016, 10:35 PM
Sounds like you're on the right track, but do let us know what Noble Company has to say about the roofing felt under the CPE liner. I don't think it's gonna be a serious problem, but I've no real evidence to back that up. Unfortunately, we no longer have our own Noble rep on board.

If you'll put a geographic location into your User Profile folks can see what part of Massachusetts your from. I think in Boston they'd want you to use copper, yes? :)

12-11-2016, 10:41 PM
Im from NYC, lots of lead in shower pans here.

Ill talk to noble tomorrow. From all the back stories on using roofing cement to glue down the liner, did something come of this that made that recommendation go away.

Noble rep was e3? I ask cause I did find an old thread where someone asked about gluing down a liner and he mentioned about it not being a problem. http://www.johnbridge.com/vbulletin/showthread.php?t=7863

Granted I am not glued down, but I am assuming the roofing cement and felt have the same nasty stuff in them.

12-11-2016, 11:42 PM
Ah, yes, think we've heard of alla lead pans in NYC. Maybe they couldn't afford copper like them rich folks in Boston. :D

Yes, e3 was our Noble rep for years. He's now with MAPEI.

Michael Byrne is the only one I've ever known to promote that black pookey under shower pan liners. Don't know if he ever got over that.

12-12-2016, 05:37 AM
What do you mean by "if he ever got over it"?

Todd Groettum
12-12-2016, 06:02 AM
Pretty sure Kelly means it isnt really needed and michael was the only one who promoted it ;)

12-12-2016, 07:22 AM
Not needed is one thing, I am worried if it was cause the CPE to degrade over time?

12-12-2016, 11:56 AM
Called Nobel. They seem to think its not a problem.

Im just on the fence on if I should just redo the pan and get it out anyway.


I was able to pull back the liner and slip out the paper, its no longer there. Gonna give it another flood test now that I did that. I'll be back here tonight to write the full back story.

12-12-2016, 06:46 PM
So ant the end of today I realized it wouldn't be to hard for me to just pull a few of the nails holding the liner to the studs and slip the sheets out. So that what I did. No more sheets. Nobel said it shouldn't have been an issue and there was even mention of Michael B. They did say that felt should NOT be used under PVC.

Tool Guy - Kg
12-12-2016, 07:25 PM
While nobody knows Noble's products as well as them and they didn't seem too bothered...

...it's still a good feeling to eliminate any lingering doubt.


12-12-2016, 08:44 PM
I like this quote:

"...it's still a good feeling to eliminate any lingering doubt"

I may use that often.

12-12-2016, 08:48 PM
Since this is my fist time using this and I actually lifted two corners of my pan today, it got me thinking, how tough is the CPE (or even PVC for that matter).

It seems the material "stretches" in the folded corners. Does it ever "work harden"? Does folding and unfolding it to set it up, get it into place, make final adjustments weaken the corner?

12-12-2016, 10:06 PM
Mike, you ain't got time to fold that stuff enough to do it any damage. Don't worry about it.

My opinion; worth price charged.

12-13-2016, 10:30 AM
Thanks CX.

So reinforcing the corner with pre-made corner dams, just a waste of time?

Todd Groettum
12-13-2016, 10:52 AM
An interesting question, does it ever work harden......

A few years back i tore out an old shower I had done back in 1988 with good ol Red Pasco pvc to build a larger ( and modernized) shower....
The liner was still in good flexible condition if you discount the hell we played with it during tear out...I believe it was oh 22 maybe 23 years old...

Dave Gobis
12-13-2016, 05:19 PM
CPE is chlorinated PVC. That helps it retain its flexibility. PVC typically becomes more brittle than CPE with age and exposure to alkalinity.